HANC’s Green Wall

On June 13 ARC staff rolled out of bed extremely early for a Saturday morning to spend the morning sweating and cursing. We arrived at the Houston Arboretum & Nature Center at 7:00 a.m. to beat the heat (or so we thought…) Awaiting us were two very cool gabion seating benches: metal cages secured to a foundation, filled with recycled crushed concrete and topped off with recycled boardwalk seating lids. John Schneider, from SpawGlass, had installed them the day before. We had no idea how much work had go into it until we turned to the task that awaited us…

The 6 ft tall green wall we planned to install was patiently sitting in place in two pieces. The first basket, 3 ft high, was already secured to the slab that SpawGlass had poured the day before. We removed the second basket, which sat on top, and began to fill the base with hoagie-sized concrete pieces. It was a good reach to the bottom of the basket, 3ft down, this meant straining to reposition the rocks that weren’t cooperating. The fun was only just beginning. After a layer or two of the concrete it was time to drape across a sheet of burlap, the intension here was to create a lining to retain the soil which we would spread in next. Native plants were added to the soil layer. They were removed from the safety of their pots and stuck, head-first, from the inside, through the cage openings, their vulnerable stalks and leaves hanging downward while the rootball was lovingly compressed between a rock and a hard place.

Another layer of concrete, another layer of burlap, another layer of soil/plants, and so the sandwich continued. There was also the added complication of the soaker hose. Yes, it was added from the ground up, snaked through the cage between layers like a ribbon of mayonnaise. All was well, until we got to the top of the first cage…now what?

We secured the cage lid, then hauled the second container up on top, deciding it needed to be secured also, but without the contractor present to advise us, we rigged some wire through to join the two cages together. We then proceeded to fill cage no. 2. Okay, this is where it got really tricky. We were already 3 ft up, and this second cage added additional 3 ft. Reaching down inside that puppy was virtually impossible. We worked as a team, tossing in rocks, thrusting the smallest of our hands through the cage to manipulate the plants as they were handed down from above. After the first two layers of plants were installed things became more manageable, but being up so high limited the workspace, so Keiji and Pat continued with the arrangement while to rest of us handed them materials.

Joe Blanton, the Arboretum’s Conservation Director had given us a variety of sedum to use as accent pieces. Some of them were pretty tall but they were perfect to top off the wall. Among the sedum were salvia and lantana. By that time it was a race to finish between Keiji and Pat. Exactly five hours since that first piece of concrete hit the bottom, and viola – it looked great! We ran the soaker hose for a while, giving care instruction to HANC. We were overheated, sweaty, achey and exhausted, but oh, so proud : )

Since June 13 there has been a lot of sun and an extreme amount of heat in Houston. The soaker hose was unintentionally disconnected for a few days and we don’t know if our green wall plantings will make it. Time will tell. We learned that the baskets should never be more than two feet deep, that native plants are great but they must be hardy individuals able to withstand the cruel and harsh conditions of heat generated within a rock and steel cage, and that sedum are probably the way to go. Making a green wall in your own back yard would be a fun project (under the right conditions…), choose your plant material carefully and remember to keep your soaker hose attached!